Chapter 43: The Immune System Flashcards
Innate immunity
Defense that is active immediately upon infection and is the same whether or not the pathogen has been encountered previously; provides outer covering like skin/shell to provide a barrier to microbes; includes chemical barriers like mucous membranes
Immune system
Defenses and responses to infection that enable animals to avoid or limit infections
What a some basic components of innate immunity?
Skin/shell, chemical sections, linings of digestive tract, airway, exchange surfaces, etc.
Molecular recognition
Receptor molecules bind specifically to molecules from foreign cells or viruses; enables self-detection
Adaptive immunity
Defense found only in vertebrates: produce a vast arsenal of receptors for features previously encountered; aka acquired immune response
True or false: adaptive immunity is activated after innate immunity and develops more slowly
True
In what kinds of animals is innate immunity found?
All animals
Chitin exoskeletons is a component of what in invertebrates?
Innate immunity
What is another component of innate immunity, besides the exoskeleton, that protects invertebrate insects?
Lysozymes: break down bacterial cell walls
Hemocytes
Immune cells that travel through the body in lymph, the insect circulatory fluid
What are some functions of hemocytes in insects?
Phagocytosis, pathogen-killing chemical production, disruption of fungal/bacterial plasma membrane, production of antimicrobial peptides
Antimicrobial peptides
Short chains of amino acids that circulate throughout insect bodies secreted by hemocytes and other cells, specific to different pathogens
Immune cells of insects bind to molecules found only where?
In outer layers of fungi or bacteria
Particular antimicrobial peptides act against what?
Different kinds of pathogens
What are some barrier defenses in vertebrates?
Skin, mucous membranes lining digestive/respiratory/urinary/reproductive tracts, saliva, tears, mucous secretions
Saliva, tears, and mucous secretions contain what?
Lysozymes that destroy bacteria
What Isabel TLR?
Toll-like receptor: binds to mlcl fragments characteristic of a set of pathogens to detect fungal and bacterial components
Neutrophils
Circulate in blood, attracted by signals from infected tissues, engulf and destroy infecting pathogens
Macrophages
Larger phagocytic cells, can migrate or reside permanently
Dendritic cells
Mainly populate tissues, also phagocytic, stimulate adaptive immunity
Eosinophils
Often found beneath mucosal surfaces, low phagocytic activity, important to defend against multicellular invaders
Natural killer cells
Circulate, release chemicals to lead to cell death
Interferons
Proteins that provide innate defense by interfering with viral infections
Complement system
~30 proteins in blood plasma, cause chemical reactions to lyse invaders
Important inflammatory signaling molecule?
Histamine
Where is histamine stored
Granules of mast cells, in connective tissue
What does histamine do
Triggers blood vessels to dilate and become more permeable, allowing macrophages and neutrophils to discharge cytokines that enhance immune response
Cytokines
Enhance immune response and promote blood flow to injury site and attract phagocytic cells
Septic shock
Overwhelming systemic inflammatory response
